Bascule-bridge.



T. E. BROWN, 1R1

BASCULE BRIDGE.

APPLICATION FILED DEC.8. 1916. 1,251,634. Patented Jan. 1,1918.

3 SHEETS-SHEET I.

T. E. BROWN, 1R.

.BASCULE BRIDGE. 7 APPLICATION FIILED DEC. 8, I916. r 1,251,634. Pasented Jan. 1,1918.

3 SHEETS-SHEET 2.

T. E. BROWN, JR.

BASCULE BRIDGE. APPLICATION FILED DEC. 8. 19m.

1,251,634. v Patehted Jan. 1,1918.

3 SHEETFSHEET 3.

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THOMAS ELLIS BROWN, JR., 0F MORRISTOWN, NEW JERSEY.

BASCULE-BRIDGE.

7 Specification of Letters Patent.

Patented Jan. 1, 1918.

Application filed December 8, 1916. Serial No. 135,785.

To all whom it may concern.-

Be it known that I, THOMAS ELLIs BROWN, J12, a citizen of the United States, and a resident of Morristown, in the county of Morris and State of New Jersey, have invented certain new and useful Improvements in Bascule-Bridges, of which the following is a specification.

This invention relates to improvements in bascule bridges.

The simplest form of bascule bridge is the ordinary heel counterbalanced trunnion type, and this form is usually adopted when the height of the bridge above the water is sufiicient to admit of its use. In many situations, however, the height is insufficient for the heel of the bridge and counterbalance to clear the water or tops of the piers, and in such cases the span must be made longer in proportion to the width of the waterway and a watertight pit must be provided into which the heel of the bridge and counterbalance may descend. The expense of construction in such cases becomes very great, and therefore the more complicated and unsightly types, with towers and counterweights above the roadway, are usually resorted to.

Cases frequently occur where the height above water is not sufficient for a simple heel balanced bridge of ordinary type, without watertight pits, and yet where the use of unsightly towers and counterweights would be very objectionable, and in ordinary heel counterbalanced trunnion bridges it is necessary to so dispose the counter-balance that the center of gravity of the entire moving mass will coincide with the center of the trunnions or pivots, and this usually requires the placing of a considerable portion of the counter-balance above the bridge deck, to the detriment of the appearance of the structure. It is therefore the object of my in vention to produce a heel balanced trunnion bridge, suitable for such cases, in which coincidence of the center of gravity and the pivot is unnecessary, and wherein therefore no counter-balance need be placed above the deck of the bridge, and by which also the use of water tight pits or unsightly towers is entirely avoided. I

To accomplish this object, I omit from th heel of the bridge, that portion of the counter-balance which it would be necessary to place above the floor level of-the bridge and also that portion which will not clear the top of the pier, and substitute therefor an equivalent counter-weight pivoted to a fixed portion of the structure and placed below the deck of said fixed portion and I operatively connect'said weight to the moving portion of the bridge.

My construction is especially useful when concrete is employed for counter-balance (which is now the general practice) as, on account of its great bulk, concrete counterbalance is very clumsy and unsightly when placed above the bridge floor.

Referring to the drawings which accompany the specification to aid the description,

Figure 1 is a side view of a bridge of my construction.

Fig. 2 is an explanatory diagram of my method of balancing, and Figs. 3 and 4 show adaptations of my invention to bridges of very low elevation.

Similar leters of reference refer to similar parts in all the figures.

Referring to Fig. l, B is a 'bascule bridge, P the pivot or trunnion about which it rotates, A, A and A are piers and D is a portion of the fixed structure which supports said pivot P. Such portions of said fixed structure as would interfere with the clearness of the drawing are indicated as broken away.

H is that portion of the counter-balance or heavy material which may conveniently be placed in the rearwardly projecting end or heel of the bridge B, rotating with said bridge B; said counterbalance H being of such dimensions that it will clear said pier A and will not project above the roadway.

W is a counter-weight which I prefer to use to complete the balance of the bridge, and which I prefer to support on the frame K which rotates about a pivot or trunnion L, said pivot L being supported preferably on a portion of the fixed structure such as D C is a strut pivotally attached to said counter-weight W at a point E at one end, and at the other end to the heel of the bridge B at a point I.

The positions of said pivot L of said counter-weight WV and the points of attachment E and I of said connecting strut C are so chosen, with relation to the weight W andthe trunnion P, as to cause said counterweight WV together with said heel counterbalance H to balance the bridge B in all its poistions, as is hereinafter explained in connection withF-ig. 2,- Y

R and R are fixed and movable portions respectively of the roadway or bridge floor, and Z being the break in the floor between them. Said break Z, said connecting strut (J and said counterbalance H are so located, t rat the said counter-balance H, strut C and end of said roadway R will clear each other and the tops of the piers A, and A when the bridge is rotated to its vertical position.

It will be understood that the aforesaid refers to one side of the bridge only; and that the parts described for one side will generally be duplicated on the other side of the bridge; but it will generally be preferable when using materials of low specific gravity (such as concrete) for counter-balance, to extend said counter-balance H and weight W the full width of the bridge.

The bridge may be operated in any suitable manner, but I prefer to use a gear segment M secured to the bridge and meshing with a pinion N on shaft 0 supported on a fixed part of the structure. Said shaft 0 may be rotated by any suitable gearing and power.

When said pinion N is rotated in the direction the reverse of the motion of the hands of a clock, said bridge 13 rises and said heel counterbalance H descends; said strut C moves downwardly and passes under said pivot P and said counterweight IV descends. lVhen said pinion X is rotated in the opposite direction bridge B descends and said counterbalance H and weight lV rise.

Said bridge l3, counterbalance H, weight W and strut C are shown in dotted lines in the positions they occupy when the bridge is completely opened to its vertical position.

Now, referring more especially to Fig. 2, to more fully explain the principle of counterbalancing the bridge in all its positions, and how the construction hereinbefore described is arrived at, 0. g. is the center of gravity of the uncounterbalanced bridge P), and l is the pivot or trunnion around which said bridge rotates. In order that said bridge B shall be balanced in all its positions by means of a counterbalance placed in the heel or rearwardly projecting end of said bridge, said heel counterbalance must be of such weight and be so placed as to make the center of gravity of the total rotating mass coincide with the pivot P; and therefore the center of gravity J of such a heel counterbalance as a. b. 0. (Z. must lie on the prolongation of the line drawn from c. 9 through the trunnion P, as indicated in Fig. 2, and also said center of gravity J of such a heel counterbalance must be suiticiently far back of the trunnion P to make the moment of said heel counterbalance around the pivot or trunnion P equal to the moment of the bridge B around said pivot or trunnion P.

The rectangle, a, b, 0, cl, represents a simple heel counterbalance of such mass, and with its center of gravity J so placed on the line 0. 9., P prolonged, as to balance the bridge. It will be obvious from the Fig. 2 that such a counter-balance a, Z), 0, cl, which we may call the theoretical counter-balance, cannot be used under the conditions shown as it projects above the roadway R and extends back so far that it would collide with the pier A were the bridge to be opened to a vertical postion. I therefore omit the interfering portion Z), c, d, h, e, f, of the said theoretical counter-balance a, Z), c, d,

leaving the non-interfering portion a, f, c, h, which we will hereinafter designate as counter-balance H. I substitute for the omitted portion 5, 0, cl, h, c, of said theoretical counter-balance, an equivalent but not necessarily equal, counter-weight W, which I place in a convenient position, preferably beneath the fixed portion R of the roadway as shown in Fig. l, and also in Fig. 2, and supportsaid weight' 'lV on pivot or trunnion L carried by some suit able part of the fixed structure, as D in Fig. l. The center of gravity G of said weight W should have the same angular position with relation to said pivot L as the center of gravity 9 of said omitted portion 1), c, (l, h, c, would have had to the trunnion P. I connect said weight W by means of a compression strut C to the heel of the bridge ll, placin said strut C parallel to the line LP joining the centers of the respective pivots of the counter-weight W and bridge I3, and place the connections E and I at equal distances from the trunnio-ns L and P respectively, and so that said strut C will clear the piers A and A when the said weight W and bridge B rotate around their respective pivots L and P. With this arrangement the angular motion of the weight lV around the pivot L will be the same as the angular motion of the omitted portion of the theoretical counter-balance Z), 0, (Z, h, c, 7", would have been around the pivot P, and by making the weight V of proper amount so that its moment around the pivot L, '21. 0. its weight multipled by its lever arm, is equal to the moment that the said omitted portion would have had around the pivot P, then the said weight IV and the heel counterbalance II will together balance the bridge in all its postions.

\Vhile I prefer to use as much heel counter-balance H as can conveniently be placed on the rearwardly extended end of the bridge B, it will be readily understood that any desirable amount of the theoretically necessary heel counterbalance a, b, 0, (Z, may be omitted and replaced by equivalent weight in the counter-weight WV; and we may also, in cases where the head room is unusually low, use a series of counter-- weights, W IV operatively connected together, as shown in Fig. 3 by the struts C C -C and in such cases we may omit the entire heel counter-balance, and replace it by such a series of weights, W W etc, by making their total eflect the equivalent of said thoretical counter-balance, a, b, 0, (Z.

Cases may occur where the height above the water is insuflicient even for the arrangements shown in Figs. 1 and 3, and we may then use the approach span as a counterweight as shown in Fig. 4.. In such cases I prefer to pivotally support the rearward end of said approach span in the frame K, (see Fig. 4) and pivotally connect the forward end of said approach span to the heel or rearwardly projecting end of the bridge at S, as by this construction the entire weight of said approach span is made effective in counter-balancing the bridge, part of said weight acting directly at S and the remaining part at I by means of the strut C. The weight of said approach span may be illcreased by the addition of concrete or other heavy material as indicated in Fig. 4.

Now having described my improvements, I claim as my invention.

1. In a bascule bridge, the combination of a counter-weight pivoted to a fixed portion of the bridge structure, and an operative connection from said counter-weight to the rearwardly extended end of the movable part of said bridge, said connection being parallel to the line joining the pivot of the counter-weight and the pivot of the bridge in all positions of said bridge.

2. In a bascule bridge, the combination of a counter-weight pivoted to a fixed portion of the bridge, and an operative connection between said counter-weight and the heel or rearwardly projecting end of the movable portion or' said bridge, adapted to move said counter-weight with the same angular motion as the angular motion of said heel end of said bridge.

3. The combination in a bascule bridge, having one end extended rearwardly beyond the pivot of said bridge, of a counter-weight pivoted to a fixed portion of the structure, and an operative strut connection between said counter-weight and said rearwardly extended end of said bridge.

ti:- The combination in a bascule bridge having one end extended rearwardly beyond its pivot, of a counter-weight pivoted to a fixed portion of the structure, said counterweight being located below the floor of said fixed portion, and an operative strut connection between said counter-weight and the rearwardly extended end of said bridge.

The combination in a bascule bridge having one end extended rearwardly beyond its pivot, of a counter-balancing weight on said rearwardly extended end, a counterweight pivoted to a fixed portion of the structure, and an operative strut connection between said counter-weight and the rearwardly extended end of said bridge.

6. The combination in a bascule bridge having one end extended rearwardly beyond its pivot, of partly counter-balancing material on said rearwardly extended end, a counter-weight pivoted to a fixed portion of the structure, and an operative strut connection between said counter-weight and said rearwardly extended end of said bridge, said counterbalancing material and said counter-weight being placed below the roadway of said bridge.

7. The combination in a bascule bridge having one end extended rearwardly beyond its pivot, of a plurality of pivoted counter-weights disposed below the roadway of said bridge and operatively connected to each other and to the rearwardly extended end of said bridge so as to counterbalance said bridge in all its positions.

8. In a bascule bridge, the combination of a counter-weight pivoted to a fixed portion of the bridge structure and located be low the roadway of said bridge, and an open ative connection from said counterweight to the movable part of said bridge, said connection being parallel to the line joining the pivot of the counterweight and the pivot of the bridge in all positions of said bridge.

9. In a bascule bridge, a counter-weight pivoted to a fixed portion of the bridge and located below the roadway of said bridge, and an operative connection between said counter-weight and the heel end of the movable portion of said bridge, and said operative connection being adapted to move said counter-weight with the same angular motion as the angular motion of the heel end of said bridge.

10. In a bascule bridge, the combination with a pivoted bridge structure of a partial counter-balancing weight thereon, a supplementary counter-balance weight pivoted on a stationary structure, and an operative connection between said partial counterbalancing weight and said supplementary counterbalance weight positioned parallel to the straight line through said pivots and equal in length to the distance between said pivots.

Signed at New York city, in the county of New York, and State of New York, this sixth day of December, A. D. 1916.

THOMAS ELLIS BROWN, JR. lNitnesses: Tnos. E. BROWN, w RITA Wniss.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. 0 

